STREPHALIBUT

Analysis of the reproductive potential to improve the sustainability of Greenland halibut fishery

Studies of the reproductive potential of the species directly measure stock productivity. The reproductive potential is determined by the growth rate of the fish, maturity, condition and fecundity relationships. Knowledge of the stock reproductive potential and factors affecting it, is essential for the assessment to achieve sustainable levels of explotation a permit the recovery of depleted stocks. The Greenland halibut (Reinhardtius hippoglossoides) has a broad distribution in the northwest Atlantic. Thus, the Greenland halibut in NAFO SA2 + Div. 3KLMNO are both within 200 miles Canadians and regulated area by NAFO waters. This stock has been a great fishery for Spain and Canada. The size of the population in this area has gradually declined. Despite its importance, the reproductive biology of Greenland halibut remains unknown. This project aims to increase understanding of various aspects of the reproduction of greenland halibut. Specifically maturity, growth, condition and fecundity. We will study type of fecundity, maturity cycles and rate of oocyte maturation. The effects of parental features (size , growth, energy condition) and water temperature on atresia, fecundity, oocyte development and viability of eggs and larvae were also examined. New methods for estimating fecundity and to determine whether individuals are mature or immature will be developed. These methods will be available for the two countries to estimate future fecundity and reproductive potential of the stock. Project results will be incorporated into the stock advice to improve scientific advice for the management of this important stock and provide best estimates of the time period and the measures necessary to allow recovery of the stock. The project involved three institutes in each country. In Spain the Institute of Marine Research (CSIC), the Spanish Institute of Oceanography (IEO) and AZTI Foundation with a total of 7 researchers involved in the project. In Canada three laboratories of  the “Fisheries and Oceans” are also invloved: The Northwest Atlantic Fisheries Centre (St. John’s), Maurice Lamontagne Institute (Mont- Joli) and St. Andrews Biological Station (St. Andrews ), with 4 researchers involved . This project takes advantage of experts and facilities of both countries, allowing a research program would not be possible in any country or institutes separately. The project is based on collaborations that have been taking place in recent years and will result in strengthening these collaborations in the future.